Society for Maternal-Fetal Medicine Special Statement: Emergency checklist, planning worksheet, and system preparedness bundle for placenta accreta spectrum.

Placenta accreta spectrum is a life-threatening complication of pregnancy that is underdiagnosed and can result in massive hemorrhage, disseminated intravascular coagulation, massive transfusion, surgical injury, multisystem organ failure, and even death. Given the rarity and complexity, most obstetrical hospitals and providers do not have comprehensive expertise in the diagnosis and management of placenta accreta spectrum. Emergency management, antenatal interdisciplinary planning, and system preparedness are key pillars of care for this life-threatening disorder. We present an updated sample checklist for emergent and unplanned cases, an antenatal planning worksheet for known or suspected cases, and a bundle of activities to improve system and team preparedness for placenta accreta spectrum.

The Underlying Molecular Mechanisms of the Placenta Accreta Spectrum: A Narrative Review.

Placenta accreta spectrum (PAS) disorders are characterized by abnormal trophoblastic invasion into the myometrium, leading to significant maternal health risks. PAS includes placenta accreta (invasion < 50% of the myometrium), increta (invasion > 50%), and percreta (invasion through the entire myometrium). The condition is most associated with previous cesarean deliveries and increases in chance with the number of prior cesarians. The increasing global cesarean rates heighten the importance of early PAS diagnosis and management. This review explores genetic expression and key regulatory processes, such as apoptosis, cell proliferation, invasion, and inflammation, focusing on signaling pathways, genetic expression, biomarkers, and non-coding RNAs involved in trophoblastic invasion. It compiles the recent scientific literature (2014-2024) from the Scopus, PubMed, Google Scholar, and Web of Science databases. Identifying new biomarkers like AFP, sFlt-1, ß-hCG, PlGF, and PAPP-A aids in early detection and management. Understanding genetic expression and non-coding RNAs is crucial for unraveling PAS complexities. In addition, aberrant signaling pathways like Notch, PI3K/Akt, STAT3, and TGF-ß offer potential therapeutic targets to modulate trophoblastic invasion. This review underscores the need for interdisciplinary care, early diagnosis, and ongoing research into PAS biomarkers and molecular mechanisms to improve prognosis and quality of life for affected women.

Assessment of ultrasound features of placenta accreta spectrum in women at high risk: association with outcome and interobserver concordance.

OBJECTIVES: To evaluate the prenatal ultrasound features associated with operative complications and to assess the interobserver agreement of prenatal ultrasound assessment with histopathologic confirmation of placenta accreta spectrum (PAS) in a cohort of high-risk patients with detailed intraoperative and histopathologic data. METHODS: This was a retrospective multicenter cohort study of patients at high risk of PAS referred for specialist perinatal care and management between January 2019 and May 2022. Deidentified ultrasound images were reviewed independently by two experienced operators blinded to clinical details, intraoperative features, outcome and histopathologic findings. The diagnosis of PAS was confirmed by failure of detachment of one or more placental cotyledons from the uterine wall at delivery, and the absence of decidua with distortion of the uteroplacental interface by fibrinoid deposition on histologic examination of the accretic areas obtained by guided sampling of partial myometrial resection or hysterectomy specimens. Patients were categorized as having a low or high likelihood of PAS at birth. Interobserver agreement of prenatal ultrasound assessment with histopathologic confirmation of PAS was assessed using the kappa statistic. Primary outcome was major operative morbidity (blood loss ≥ 2000 mL, unintentional injury to the viscera, admission to intensive care unit or death). RESULTS: A total of 102 women at high risk of PAS were referred, of whom 66 had evidence of PAS at birth and 36 did not. When blinded to other clinical details, the examiners agreed on the low or high probability of PAS, according to ultrasound features, in 75/102 cases (73.5%). The kappa statistic was 0.47 (95% CI, 0.28-0.66), showing moderate agreement. Morbidity was twice as common with concordant prenatal diagnosis of PAS vs concordant diagnosis of not PAS. Concordant assessment of high probability of PAS was associated with the highest morbidity (66.6%) and a very high (97.6%) likelihood of histopathologic confirmation. CONCLUSIONS: The probability of histopathologic confirmation is very high with concordant prenatal assessment suggestive of PAS. The interobserver agreement for preoperative assessment with histopathologic confirmation of PAS is only moderate. Morbidity is associated with both histopathologic diagnosis and concordant antenatal assessment of PAS. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Diagnostic accuracy of ultrasound in the diagnosis of Placenta accreta spectrum: systematic review and meta-analysis.

OBJECTIVE: To evaluate the diagnostic accuracy of ultrasound and in the diagnosis of Placenta accreta spectrum (PAS). DATA SOURCES: Screening of MEDLINE, CENTRAL, other bases from inception to February 2022 using the keywords related to placenta accreta, increta, percreta, morbidly adherent placenta, and preoperative ultrasound diagnosis. STUDY ELIGIBILITY CRITERIA: All available studies- whether were prospective or retrospective- including cohort, case control and cross sectional that involved prenatal diagnosis of PAS using 2D or 3D ultrasound with subsequent pathological confirmation postnatal were included. Fifty-four studies included 5307 women fulfilled the inclusion criteria, PAS was confirmed in 2025 of them. STUDY APPRAISAL AND SYNTHESIS METHODS: Extracted data included settings of the study, study type, sample size, participants characteristics and their inclusion and exclusion criteria, Type and site of placenta previa, Type and timing of imaging technique (2D, and 3D), severity of PAS, sensitivity and specificity of individual ultrasound criteria and overall sensitivity and specificity. RESULTS: The overall sensitivity was 0.8703, specificity was 0.8634 with -0.2348 negative correlation between them. The estimate of Odd ratio, negative likelihood ratio and positive likelihood ratio were 34.225, 0.155 and 4.990 respectively. The overall estimates of loss of retroplacental clear zone sensitivity and specificity were 0.820 and 0.898 respectively with 0.129 negative correlation. The overall estimates of myometrial thinning, loss of retroplacental clear zone, the presence of bridging vessels, placental lacunae, bladder wall interruption, exophytic mass, and uterovesical hypervascularity sensitivities were 0.763, 0.780, 0.659, 0.785, 0.455, 0.218 and 0.513 while specificities were 0.890, 0.884, 0.928, 0.809, 0.975, 0.865 and 0.994 respectively. CONCLUSIONS: The accuracy of ultrasound in diagnosis of PAS among women with low lying or placenta previa with previous cesarean section scars is high and recommended in all suspected cases. TRIAL REGISTRATION: Number CRD42021267501.

Uterine artery embolization for postpartum hemorrhage with placenta accreta spectrum.

BACKGROUND: The reported success rate of uterine artery embolization (UAE) for postpartum hemorrhage (PPH) differs by the cause of bleeding; in some reports, UAE shows less successful results in patients with placenta accreta spectrum (PAS). PURPOSE: To evaluate the outcome of UAE for treating PPH associated with PAS. MATERIAL AND METHODS: From September 2011 to September 2021, 227 patients (mean age = 34.67±4.06 years; age range = 19-47 years) underwent UAE for managing intractable PPH. Patients were divided into two groups: those with PAS (n = 46) and those without PAS (n = 181). Delivery details, embolization details, and procedure-related outcomes were compared between the two groups. P values <0.05 were considered statistically significant. RESULTS: The technical success rate was 96.9% (n = 222) and the clinical success rate was 93.8% (n = 215). There were no significant differences in outcome of UAE between the two patient groups. The technical success rate was 95.7% (n = 44) in patients with PAS and 98.3% (n = 178) in patients without PAS (P = 0.267). The clinical success rate was 91.3% (n = 42) in patients with PAS and 95.6% (n = 173) in patients without PAS (P = 0.269). There were 24 cases of immediate complications, including pelvic pain (n = 20), urticaria (n = 3), and puncture site hematoma (n = 1). No major complication was reported. CONCLUSION: UAE is a safe and effective method to control intractable PPH for patients with or without PAS.

The effectiveness of single ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation in managing placenta accreta spectrum (PAS) disorder.

OBJECTIVE: To evaluate the feasibility and effectiveness of single ultrasound-guided high-intensity focused ultrasound (USgHIFU) ablation in managing placenta accreta spectrum (PAS) disorder. MATERIALS AND METHODS: We retrospectively analyzed 40 PAS patients between April 2017 and October 2021. All the patients received one session of HIFU treatment. Regular follow-up was done after HIFU treatment until normal menstruation returned and placental tissue disappeared. The patient's reproductive-related outcomes were obtained through telephone interviews. RESULTS: The median follow-up time for the 40 patients was 30.50 (15.75-44.00) months and the mean placental tissue elimination time was 45.29 ± 33.32 days. The mean duration of bloody lochia was 13.43 ± 10.01 days, with no incidences of severe bleeding. Notably, Linear regression analysis showed that the residual placenta volume before HIFU was a factor affecting the duration of bloody lochia after HIFU (R2 = 0.284, B = 0.062, P = 0.000). The normal menstrual return time was 58.71 ± 31.14 days. One (2.50%) patient developed an infection. Two (5.00%) patients were subjected to ultrasound-guided suction curettage for persistent vaginal discharge for more than one month without infection. Notably, 7 of the 18 patients who expressed reproductive plans became pregnant during the 4 to 53 months of follow-up without placental abnormalities. The remaining 11 patients were on contraceptives. CONCLUSIONS: Single HIFU is an effective treatment option for managing PAS. However, future studies on further treatment strategies to reduce complications and promote patient recovery after HIFU ablation are desirable.

Can immunohistochemistry improve the pathological diagnosis of placenta accreta spectrum (PAS) disorders?

PURPOSE: The term of placenta accreta spectrum (PAS) disorder includes all grades of abnormal placentation. It is crucial for pathologist provide standardized diagnostic assessment to evaluate the outcome of management strategies. Moreover, a correct and safe diagnosis is useful in the medico-legal field when it becomes difficult for the gynecologist to demonstrate the suitability and legitimacy of demolitive treatment. The purposes of our study were: (1) to assess histopathologic features according to the recent guidelines; (2) to determine if immunohistochemistry can be useful to identify extravillous trophoblast (EVT) and to measure the depth of infiltration into the myometrium to improve the diagnosis of PAS. METHODS: The retrospective study was conducted on 30 cases of gravid hysterectomy with histopathologic diagnosis of PAS. To identify the depth of EVT, immunohistochemical stainings were performed using anti MNF116 (cytokeratins 5, 6, 8, 17, 19), actin-SM, HPL (Human Placental Lactogen), vimentin and GATA3 antibodies. RESULTS: Our cases were graded based on the degree of invasion of the myometrium. Ten were grade 1 (33.3%), 12 grade 2 (40%) and 8 grade 3A (26.7%). EVT invasion was best seen and evident by double immunostainings with actin-SM and cytokeratins, actin-SM and HPL, actin-SM and GATA3. CONCLUSION: The role of pathologist is decisive to determine the different grades of PAS. A better understanding of the depth of myometrial invasion can be achieved by the use of immunohistochemistry affording an important tool to obtain reproducible grading of PAS. This purpose is crucial in the setting of postoperative quality reviews and particularly in the forensic medicine field.

Placenta increta in an unscarred and bicornute uterus.

Morbidly adherent placenta is a spectrum of obstetric complication which is life threatening to both mother and fetus. Congenital uterine malformation is a rare cause of such a condition. Here we present a case report of placenta increta in bicornute, unscarred uterus. An 18 year old para1+1 presented in emergency with history of vaginal delivery of still birth baby followed by vaginal bleeding with retained placenta. Her Examination under anaesthesia and failed attempt of manual removal of the placenta performed in emergency followed by Doppler ultrasound showed a bicornuate uterus with possibility of placenta increta, later this diagnosis was confirmed on magnetic resonance imaging (MRI). Patient managed with injection methotrexate along with folinic acid followed by removal of placenta under general anesthesia, hence we preserved her fertility. The aim of this report is to emphasize the importance of this rare but a possible association of nonscar and malformed uterus with spectrum of abnormal placentation. Obstetrician should run a full set of investigations in such cases to prevent maternal and fetal mortality and morbidity.

[Establishment of Decision Tree Prediction Model for Risk Factors of Placenta Accreta Spectrum Disorders].

Objective: To analyze the risk factors for placenta accreta spectrum (PAS) disorders and to construct preliminarily a decision tree prediction model for PAS, to help identify high-risk populations, and to provide reference for clinical prevention and treatment. Methods: By accessing the electronic medical record system, we retrospectively analyzed the relevant data of 2022 women who gave birth between January 2020 and September 2020 in a hospital in Chengdu. Univariate logistic regression and multivariate logistic regression were conducted to analyze the risk factors of PAS. SPSS Clementine12.0 was used to make preliminary exploration for the decision tree prediction model of PAS risk factors. Results: Results of logistic regression suggested that the top three risk factors for PAS included the following, the risk of PAS in pregnant women with placenta previa was 8.00 times that in pregnant women without placenta previa (95% CI: 5.24-12.22), the risk of PAS in multiple pregnancies was 2.52 times that in singleton pregnancies (95% CI: 1.72-3.69), and the risk of PAS in pregnant women who have had three or more abortions was 1.89 times that in those who have not had abortion (95% CI: 1.11-3.20). Results of the decision tree prediction model based on C5.0 algorithm were as follows, placenta previa was the most important risk factor, with as high as 93.33% (140/150) patients developed PAS when they had placenta previa; when in vitro fertilization-embryo transfer (IVF-ET) was the only factor the subjects had, the incidence of PAS was 59.91% (133/222); the incidence of PAS was as high as 75.96% (79/104) when the subjects had both IVF-ET and a history of uterine surgery; the probability of PAS in women who had induced abortion in the past was 48.46% (205/423); the probability of PAS in women who had undergone uterine surgery previously was 10.54% (37/351); the incidence of PAS was as high as 100.00% (163/163) when the subjects had induced abortion previously and uterine surgery history. The model showed a prediction accuracy of 85.41% for the training set and a prediction accuracy of 83.36% for the testing set, both being high rates of accuracy. Conclusion: The decision tree prediction model can be used for rapid and easy screening of patients at high risk for PAS, so that the likelihood of PAS can be actively and dynamically assessed and individualized preventive measures can be taken to avoid adverse outcomes.

Failure of placental detachment in accreta placentation is associated with excessive fibrinoid deposition at the utero-placental interface.

BACKGROUND: The main histopathologic diagnostic criteria for the diagnosis of placenta accreta for more than 80 years has been the finding of a direct attachment of the villous tissue to the superficial myometrium or adjacent to myometrial fibers without interposing decidua. There have been very few detailed histopathologic studies in pregnancies complicated by placenta accreta spectrum disorders and our understanding of the pathophysiology of the condition remains limited. OBJECTIVE: To prospectively evaluate the microscopic changes used in grading and to identify changes that might explain the abnormal placental tissue attachment. STUDY DESIGN: A total of 40 consecutive cesarean delivery hysterectomy specimens for placenta previa accreta at 32 to 37 weeks of gestation with at least 1 histologic slide showing deeply implanted villi were analyzed. Prenatal ultrasound examination included placental location, myometrial thickness, subplacental vascularity and lacunae. Macroscopic changes of the lower segment were recorded during surgery and areas of abnormal placental adherence were sampled for histology. In addition, 7 hysterectomy specimens with placenta in-situ from the Boyd Collection at 20.5 to 32.5 weeks were used as controls. RESULTS: All 40 patients had a history of at least 2 previous cesarean deliveries and presented with a mainly anterior placenta previa. Of note, 37 (92.5%) cases presented with increased subplacental vascularity, 31 (77.5%) cases with myometrial thinning and all with lacunae. Furthermore, 20 (50%) cases presented with subplacental hypervascularity, lacunae score of >3, and lacunae feeder vessels. Intraoperative findings included anterior lower segment wall increased vascularization in 36 (90.0%) cases and extended area of dehiscence in 18 (45.0%) cases. Immediate gross examination of hysterectomy specimens showed an abnormally attached areas involving up to 30% of the basal plate, starting at <2 cm from the dehiscence area in all cases. Histologic examination found deeply implanted villi in 86 (53.8%) samples with only 17 (10.6%) samples presenting with villous tissue reaching at least half the uterine wall thickness. There were no villi crossing the entire thickness of the uterine wall. There was microscopic evidence of myometrial scarification in all cases. Dense fibrinoid deposits, 0.5 to 2 mm thick, were found at the utero-placental interface in 119 (74.4%) of the 160 samples between the anchoring villi and the underlying uterine wall at the accreta areas and around all deeply implanted villi. In the control group, the Nitabuch stria and basal plate became discontinuous with advancing gestation and there was no evidence of fibrinoid deposition at these sites. CONCLUSION: Samples from accreta areas at delivery present with a thick fibrinoid deposition at the utero-placental interface on microscopic examination independently of deeply implanted villous tissue in the sample. These changes are associated with distortion of the Nitabuch membrane and might explain the loss of parts of the physiological site of detachment of the placenta from the uterine wall in placenta accreta spectrum. These findings indicate that accreta placentation is more than direct attachment of the villous tissue to the superficial myometrium and support the concept that accreta villous tissue is not truly invasive.

Prospective evaluation of impact of post-Cesarean section uterine scarring in perinatal diagnosis of placenta accreta spectrum disorder.

OBJECTIVE: Standardized ultrasound imaging and pathology protocols have recently been developed for the perinatal diagnosis of placenta accreta spectrum (PAS) disorders. The aim of this study was to evaluate prospectively the effectiveness of these standardized protocols in the prenatal diagnosis and postnatal examination of women presenting with a low-lying placenta or placenta previa and a history of multiple Cesarean deliveries (CDs). METHODS: This was a prospective cohort study of 84 consecutive women with a history of two or more prior CDs presenting with a singleton pregnancy and low-lying placenta/placenta previa at 32-37 weeks' gestation, who were referred for perinatal care and management between 15 January 2019 and 15 December 2020. All women were investigated using the standardized description of ultrasound signs of PAS proposed by the European Working Group on abnormally invasive placenta. In all cases, the ultrasound features were compared with intraoperative and histopathological findings. Areas of abnormal placental attachment were identified during the immediate postoperative gross examination and sampled for histological examination. The data of a subgroup of 32 women diagnosed antenatally as non-PAS who had complete placental separation at birth were compared with those of 39 cases diagnosed antenatally as having PAS disorder that was confirmed by histopathology at delivery. RESULTS: Of the 84 women included in the study, 42 (50.0%) were diagnosed prenatally as PAS and the remaining 42 (50.0%) as non-PAS on ultrasound examination. Intraoperatively, 66 (78.6%) women presented with a large or extended area of dehiscence and 52 (61.9%) with a dense tangled bed of vessels or multiple vessels running laterally and craniocaudally in the uterine serosa. A loss of clear zone was recorded on grayscale ultrasound imaging in all 84 cases, while there was no case with bladder-wall interruption or with a focal exophytic mass. Myometrial thinning (< 1 mm) in at least one area of the anterior uterine wall was found in 41 (97.6%) of the 42 cases diagnosed as non-PAS on ultrasound and 37 (88.1%) of the 42 diagnosed antenatally as PAS. Histological samples were available for all 48 hysterectomy specimens with abnormal placental attachment and for the three cases managed conservatively with focal myometrial resection and uterine reconstruction. Villous tissue was found directly attached to the superficial myometrium (placenta creta) in six of these cases and both creta villous tissue and deeply implanted villous tissue within the uterine wall (placenta increta) were found in the remaining 45 cases. There was no evidence of percreta placentation on histology in any of the PAS cases. Comparison of the main antenatal ultrasound signs and perioperative macroscopic findings between the two subgroups correctly diagnosed antenatally (32 non-PAS and 39 PAS) showed no significant difference with respect to the distribution of myometrial thinning and the presence of a placental bulge on ultrasound and of anterior uterine wall dehiscence intraoperatively. Compared with the non-PAS subgroup, the PAS subgroup showed significantly higher placental lacunae grade (P < 0.001) and more often hypervascularity of the uterovesical/subplacental area (P < 0.001), presence of bridging vessels (P = 0.027) and presence of lacunae feeder vessels (P < 0.001) on ultrasound examination, and increased vascularization of the anterior uterine wall intraoperatively (P < 0.001). CONCLUSIONS: Remodeling of the lower uterine segment following CD scarring leads to structural abnormalities of the uterine contour on both ultrasound examination and intraoperatively, independently of the presence of accreta villous tissue on microscopic examination. These anatomical changes are often reported as diagnostic of placenta percreta, including cases with no histological evidence of PAS. Guided histological examination could improve the overall diagnosis of PAS and is essential to obtain evidence-based epidemiologic data. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Evaluation of classic and novel ultrasound signs of placenta accreta spectrum.

OBJECTIVES: Improvement in the antenatal diagnosis of placenta accreta spectrum (PAS) would allow preparation for delivery in a referral center, leading to decreased maternal morbidity and mortality. Our objectives were to assess the performance of classic ultrasound signs and to determine the value of novel ultrasound signs in the detection of PAS. METHODS: This was a retrospective cohort study of women with second-trimester placenta previa who underwent third-trimester transvaginal ultrasound and all women with PAS in seven medical centers. A retrospective image review for signs of PAS was conducted by three maternal-fetal medicine physicians. Classic signs of PAS were defined as placental lacunae, bladder-wall interruption, myometrial thinning and subplacental hypervascularity. Novel signs were defined as small placental lacunae, irregular placenta-myometrium interface (PMI), vascular PMI, non-tapered placental edge and placental bulge towards the bladder. PAS was diagnosed based on difficulty in removing the placenta or pathological examination of the placenta. Multivariate regression analysis was performed and receiver-operating-characteristics (ROC) curves were generated to assess the performance of combined novel signs, combined classic signs and a model combining classic and novel signs. RESULTS: A total of 385 cases with placenta previa were included, of which 55 had PAS (28 had placenta accreta, 11 had placenta increta and 16 had placenta percreta). The areas under the ROC curves for classic markers, novel markers and a model combining classic and novel markers for the detection of PAS were 0.81 (95% CI, 0.75-0.88), 0.84 (95% CI, 0.77-0.90) and 0.88 (95% CI, 0.82-0.94), respectively. A model combining classic and novel signs performed better than did the classic or novel markers individually (P = 0.03). An increasing number of signs was associated with a greater likelihood of PAS. With the presence of 0, 1, 2 and ≥ 3 classic ultrasound signs, PAS was present in 5%, 24%, 57% and 94% of cases, respectively. CONCLUSIONS: We have confirmed the value of classic ultrasound signs of PAS. The use of novel ultrasound signs in combination with classic signs improved the detection of PAS. These findings have clinical implications for the detection of PAS and may help guide the obstetric management of patients diagnosed with these placental disorders. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Percreta score to differentiate between placenta accreta and placenta percreta with ultrasound and MR imaging.

INTRODUCTION: The objective of this study was to assess the performance of ultrasound and magnetic resonance imaging (MRI) features in helping to classify the type of placenta accreta spectrum (PAS; accreta/increta vs percreta), alone or combined in a predictive score. MATERIAL AND METHODS: We conducted a retrospective study in 82 pregnant women with PAS who underwent ultrasound and MRI examination of the pelvis before delivery (from an initial cohort of 185 women with PAS). We estimated the sensitivity, specificity and accuracy of MRI and ultrasound in the diagnosis of the type of PAS. We analyzed cesarean and imaging features using univariable logistic regression analysis. We constructed a nomogram to predict the risk of placenta percreta and validated it with bootstrap resampling, then used receiver operating characteristic curves to assess the performance of the model in distinguishing between placenta percreta and placenta accreta/increta. RESULTS: Among the 82 patients, 29 (35%) had placenta accreta/increta and 53 (65%) had placenta percreta. The best features to discriminate between placenta accreta/increta and placenta percreta with ultrasound were increased vascularization at the uterine serosa-bladder wall interface (odds ratio [OR] 7.93; 95% confidence interval [CI] 2.78-24.99; p < 0.01) and the number of lacunae without a hyperechogenic halo (OR 1.36; 95% CI 1.14-1.67; p = 0.012). Concerning MRI markers, heterogeneous placenta (OR 12.89; 95% CI 3.05-89.16; p = 0.002), dark intraplacental bands (OR 12.89; 95% CI 3.05-89.16; p = 0.002) and bladder wall interruption (OR 15.89; 95% CI 4.78-73.33; p < 0.001) had a higher OR in discriminating placenta accreta/increta from placenta percreta. The nomogram yielded areas under the curve of 0.841 (95% CI 0.754-0.927) and 0.856 (95% CI 0.767-0.945), after bootstrap resampling, for the accurate prediction of placenta percreta. CONCLUSIONS: The nomogram we developed to predict the risk of placenta percreta among patients with PAS had good discriminative capabilities. This performance and its impact on maternal morbidity should be confirmed by future prospective studies.

Outcomes of pregnancies at high-risk for placenta accreta spectrum following negative diagnostic imaging.

OBJECTIVES: To assess the pretest and negative post-test probability for placenta accreta spectrum (PAS) in a group of patients with high-risk clinical factors. METHODS: We included patients with suspected and/or confirmed PAS at our institution over 8 years. Sonography performed by maternal-fetal medicine specialists, and selected patients underwent MRI. Imaging was considered positive if either sonography or MRI suggested PAS. Histopathology was the gold standard for diagnosis of PAS. We assessed the pretest and negative imaging-test probability, and resources required. RESULTS: We identified 82 high-risk patients with the following: (1) a history of ≥1 cesarean section and/or intrauterine gynecologic procedure and placenta previa in the index pregnancy; (2) a history of >3 cesarean deliveries and/or gynecologic procedures regardless of placental location; (3) prior PAS disorder, or retained placenta requiring manual extraction and/or curettage, complicated by postpartum hemorrhage; and (4) suspected cesarean section scar pregnancy. Histopathology confirmed PAS in 52 patients, with pretest probability of 63%. Imaging correctly identified 44/50 cases with PAS, and excluded this condition in 24/30 cases. Thus, the positive and negative post-test probability for PAS following negative imaging was 88 and 20%, respectively. Of the six patients with false-negative imaging, all had either surgical complications or required care beyond that for routine cesarean section. CONCLUSIONS: Although diagnostic imaging is sensitive, the negative posttest probability remains high in women with high pretest probability for PAS. Therefore, women at high risk for PAS should be managed in experienced centers by a multidisciplinary team even if imaging is negative.

Early detection of a cesarean scar pregnancy with placenta increta by contrast-enhanced ultrasound in the first trimester: A case report and literature review.

Cesarean scar pregnancy (CSP) is a rare form of ectopic pregnancy, which is a long-term complication of cesarean section. Prompt and accurate diagnosis of CSP is important to decrease maternal mobility and mortality. However, it is difficult to make an early detection for CSP complicated with morbidly adherent placenta. Contrast-enhanced ultrasound with the advantage in blood flow imaging is low-cost, time-saving, safe and more accessible in clinical practice. Here, we report a case with early detection of CSP with placenta increta by contrast-enhanced ultrasound and its successful uterine-sparing surgical management.

A comparison of results following the treatment of placenta accreta and placenta increta using high-intensity focused ultrasound followed by hysteroscopic resection.

OBJECTIVE: To compare the safety and efficacy of high-intensity focused ultrasound (HIFU) followed by hysteroscopic resection for different placenta accreta spectrum disorders. MATERIALS AND METHODS: Thirty-four patients with placenta accreta, placenta increta, or placenta percreta were treated with USgHIFU from January 2016 to December 2019 and were retrospectively reviewed. The patients were classified into three categories according to the relationship between the trophoblastic villi and the myometrium, based on magnetic resonance imaging (MRI). Fifteen patients were classified as placenta accreta, 17 patients were classified as placenta increta, and 2 were classified as placenta percreta. All patients completed follow-up. Treatment efficacy and safety were evaluated. RESULTS: No significant differences in baseline characteristics and results of HIFU ablation were observed between the patients with placenta accreta and those with placenta increta. The return of HCG levels to normal was longer in patients with placenta accreta compared with patients with placenta increta, while no significant difference was observed in the amount of intraoperative blood loss, the return of normal menstruation and the length of hospital stay. CONCLUSIONS: HIFU treatment followed by hysteroscopic resection is safe and effective in the treatment of patients with placenta accreta and placenta increta.

Diagnosis pitfall of interstitial pregnancy: a case report of a term pregnancy with abnormal placentation.

BACKGROUND: Interstitial Pregnancy (IP) is a lethal condition due to high risk of sudden onset massive hemorrhage. Such conditions are managed as soon as diagnosed almost in the first trimester. There are a few case reports of IP conditions terminated after the second trimester. Herein, we introduce a term interstitial pregnancy complicated by abnormal placentation. CASE PRESENTATION: In this case report, we introduce a 32-year-old lady, primigravida, with an undiagnosed IP that was in her 38 weeks of gestational with placenta increta. She developed with perforated IP presenting with acute abdomen and internal bleeding at 26 weeks of gestational age. However, with a misdiagnosis impression, she got stable in operation room. Then, the pregnancy continued till 36 weeks of gestational age that was misdiagnosed with cervical cancer in prenatal work-ups. Finally, during elective cesarean section at 38 weeks, an IP with placenta increta (placenta evading from the serosa to the myometrium of the uterus) was observed. The baby was healthy with no obvious anomaly or morbidity. CONCLUSIONS: Physicians should be aware to detect IP in all trimesters and pay attention to the coexisting complications such as placenta accreta to manage them more accurately.

Predicting Placenta Accreta Spectrum: Validation of the Placenta Accreta Index.

OBJECTIVES: The placenta accreta spectrum (PAS) incidence has risen substantially over the past century, paralleling a rise in cesarean delivery (CD) rates. Prenatal diagnosis of PAS improves maternal outcomes. The Placenta Accreta Index (PAI) is a standardized approach to prenatal diagnosis of PAS incorporating clinical risk and ultrasound (US) findings suggestive of placental invasion. We sought to validate the PAI for prediction of PAS in pregnancies with prior CD. METHODS: This work was a retrospective cohort study of pregnancies with 1 or more prior CDs that received a US diagnosis of placenta previa or low-lying placenta in the third trimester. Images of third-trimester US with a complete placental evaluation were read by 2 blinded physicians, and the PAI was applied. Surgical outcomes and pathologic findings were reviewed. Placenta accreta spectrum was diagnosed if clinical evidence of invasion was seen at time of delivery or if any placental invasion was identified histologically. International Federation of Gynecology and Obstetrics criteria were used. RESULTS: A total of 194 women met inclusion criteria. Cesarean hysterectomy was performed in 92 (47%), CD in 97 (50%), and vaginal delivery in 5 (3%). Of those who underwent hysterectomy, PAS was histologically confirmed in 79 (85%) pregnancies. Of the remaining 13 who underwent hysterectomy, all met International Federation of Gynecology and Obstetrics grade 1 clinical criteria for PAS. With a threshold of greater than 4, the PAI has a sensitivity of 87%, specificity of 77%, positive predictive value of 72%, and negative predictive value of 90% for PAS diagnosis. CONCLUSIONS: Contemporaneous application of the PAI, a standardized approach to US diagnosis, is useful in the prenatal prediction of PAS.

Outcomes following a clinical algorithm allowing for delayed hysterectomy in the management of severe placenta accreta spectrum.

BACKGROUND: The incidence of placenta accreta spectrum is rising. Management is most commonly with cesarean hysterectomy. These deliveries often are complicated by massive hemorrhage, urinary tract injury, and admission to the intensive care unit. Up to 60% of patients require transfusion of ≥4 units of packed red blood cells. There is also a significant risk of death of up to 7%. OBJECTIVE: The purpose of this study was to assess the outcomes of patients with antenatal diagnosis of placenta percreta that was managed with delayed hysterectomy as compared with those patients who underwent immediate cesarean hysterectomy. STUDY DESIGN: We performed a retrospective study of all patients with an antepartum diagnosis of placenta percreta at our large academic institution from January 1, 2012, to May 30, 2018. Patients were treated according to standard clinical practice that included scheduled cesarean delivery at 34-35 weeks gestation and intraoperative multidisciplinary decision-making regarding immediate vs delayed hysterectomy. In cases of delayed hysterectomy, the hysterotomy for cesarean birth used a fetal surgery technique to minimize blood loss, with a plan for hysterectomy 4-6 weeks after delivery. We collected data regarding demographics, maternal comorbidities, time to interval hysterectomy, blood loss, need for transfusion, occurrence of urinary tract injury and other maternal complications, and maternal and fetal mortality rates. Descriptive statistics were performed, and Wilcoxon rank-sum and chi-square tests were used as appropriate. RESULTS: We identified 49 patients with an antepartum diagnosis of placenta percreta who were treated at Vanderbilt University Medical Center during the specified period. Of these patients, 34 were confirmed to have severe placenta accreta spectrum, defined as increta or percreta at the time of delivery. Delayed hysterectomy was performed in 14 patients: 9 as scheduled and 5 before the scheduled date. Immediate cesarean hysterectomy was completed in 20 patients: 16 because of intraoperative assessment of resectability and 4 because of preoperative or intraoperative bleeding. The median (interquartile range) estimated blood loss at delayed hysterectomy of 750 mL (650-1450 mL) and the sum total for delivery and delayed hysterectomy of 1300 mL (70 -2150 mL) were significantly lower than the estimated blood loss at immediate hysterectomy of 3000 mL (2375-4250 mL; P<.01 and P=.037, respectively). The median (interquartile range) units of packed red blood cells that were transfused at delayed hysterectomy was 0 (0-2 units), which was significantly lower than units transfused at immediate cesarean hysterectomy (4 units [2-8.25 units]; P<.01). Nine of 20 patients (45%) required transfusion of ≥4 units of red blood cells at immediate cesarean hysterectomy, whereas only 2 of 14 patients (14.2%) required transfusion of ≥4 units of red blood cells at the time of delayed hysterectomy (P=.016). There was 1 maternal death in each group, which were incidences of 7% and 5% in the delayed and immediate hysterectomy patients, respectively. CONCLUSION: Delayed hysterectomy may represent a strategy for minimizing the degree of hemorrhage and need for massive blood transfusion in patients with an antenatal diagnosis of placenta percreta by allowing time for uterine blood flow to decrease and for the placenta to regress from surrounding structures.

Recurrence of post-partum hemorrhage in women with a history of uterine artery embolization.

AIM: To evaluate pregnancy outcome and complications in subsequent pregnancies after severe post-partum hemorrhage (PPH) between women with and without a history of uterine artery embolization (UAE). METHODS: Women who had a history of severe PPH, and delivered newborns at ≥22 gestational weeks in subsequent pregnancies were enrolled. Severe PPH was defined as blood loss volume of more than 2000 mL. RESULTS: The blood loss volume (median 1581 mL) in women with UAE (n = 14) was significantly more than that in women without UAE (median 1021 mL, n = 32, P < 0.01), and the recurrence rate of severe PPH in women with UAE (n = 5, 35.7%) was significantly higher than that in women without UAE (n = 3, 9.4%, P < 0.05). There were no significant differences in frequencies of premature delivery, hypertensive disorders of pregnancy, fetal growth restriction, or placenta previa/low lying placenta. Of 14 women with UAE, 7 (50.0%) had abnormally invasive placenta, whereas of 32 women without UAE, none had abnormally invasive placenta. CONCLUSION: Subsequent pregnancies after UAE for severe PPH had high risks for recurrence of severe PPH.